For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningInstallation Procedure
Prepare all mating surfaces as necessary.
Align the body lock pillar outer panel reinforcement.
Create 8 x 24 mm (5/16 x 15/16 in) slots for MIG-brazing upper (1) and
lower (2).
Clean and prepare the attaching surfaces for spot welding and brazing.
Position the body loc ...
Installation Procedure
Create 5 x 18 mm (4/16 x 11/16 in) slots for MIG-brazing along the edges
of the tail lamp pocket as noted f rom the
original panel.
Note:
Clean and prepare the attaching surfaces for brazing.
Position the tail lamp pocket on the vehicle.
Verify the fit of the ta ...
Safety Locks
The rear door safety locks prevent passengers from opening the rear doors from
inside the vehicle.
Press to activate the safety locks.
The indicator light comes on when activated.
The rear door power windows are also disabled.
Press again to deactivate the safety
locks and power windows ...